Research on the Stirring Characteristics of Small and Medium-Sized Converters Based on a Staggered Oxygen Lance

This study systematically investigates the influence of a staggered oxygen lance on the stirring characteristics of the molten bath in a 120-ton converter using a combination of physical experiments and numerical simulations. The main findings are as follows: Compared with the traditional oxygen lance, the staggered configuration of large and small holes for the staggered oxygen lance significantly enhances the jet impingement effect on the molten bath. This results in increases in average cavity depth and diameter of 5.14% and 3.79%, respectively, thereby effectively shortening the mixing time and improving stirring efficiency by 17% to 23.6%. Mixing time decreases with increasing flow rate. As lance height increases, mixing time initially decreases and then increases, with the optimal lance height identified as H = 35d_e. For the staggered oxygen lance, the shortest mixing time is achieved at a flow rate ratio of 65%/35%. Further analysis reveals that the staggered oxygen lance (65%/35%) significantly enhances the turbulent kinetic energy at the bath surface. It increases the volume of the active flow zone by 12.1%, reduces the dead zone volume by 11.7%, and raises the volume-averaged velocity of the molten steel by 5.6%.